Latest post

Mar 7, 2025, 23:36:20

I just found out that my progress in the game Filament is lost. I thought Epic Games has cloud save for it, but after some digging, I found out the source of all the tragedy. The synced dir is %LOCALAPPDATA%\Filament\Saved\SavedGames while the actual place for save files is %LOCALAPPDATA%\Filament\Saved\SaveGames. No kidding. Just like that. Lost.

#gaming #puzzlegame #filament #epicgames

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Articles

  • Feb 1, 2023

    Defend our earth against aliens’ bullets!

    The aliens intiated their attack to the earth! They shoot bullets with mass mm and speed vv from a far-awar planet. To defend, humans built a field U=α/rU=\alpha/r that can repel the bullets. What regions are safe? The answer turns out to be the interior of a circular paraboloid.

  • Jan 18, 2023

    This is what will happen after you get a haircut

    Denote the length distribution of one’s hair to be f(l,t)f(l,t), where ll is hair length, and tt is time. Considering that each hair may be lost naturally from time to time (there is a probability of λ dt\lambda\,\mathrm dt for each hair to be lost within time range from tt to t+dtt+\mathrm dt) and then restart growing from zero length, how will the length distribution of hair evolve with time? It turns out that we may model it with a first-order PDE.

  • Jan 11, 2023

    I want to invent a better way to read numbers

    Reading numbers in English is a pain. I want to invent a better way to read numbers!

  • Dec 25, 2022

    The longest all-11 substring of a random bit string

    Given your probability of breaking the combo at each note, what is the probability distribution of your max combo in the rhythm game chart? I considered the problem seriously!

  • Dec 5, 2022

    I made this, for the number of days in a week is prime

    The number of days in a week is prime, so we cannot utilize weekly periods to help us remember periodical events unless the period is a multiple of 7. However, there may be something that we need to get reminded of which happens once per two days or three days. For example, I wash my hair once per two days and wash my clothes once per eight days. To solve the problem, I wrote a Ruby program to help remind me of those routines.

  • Nov 28, 2022

    Using ntfy to warn me when my computer is discharging

    I use udev and systemd to send a notification to my phone via ntfy automatically whenever my laptop is discharging.

  • Nov 20, 2022

    How to construct mechanics in higher dimensions?

    We can derive the equation of motion for mechanical systems in a Galileo universe with ι\iota time dimensions and χ\chi space dimensions by generalizing the principle of relativity and Hamilton’s principle.

  • Nov 18, 2022

    When a supersonic airplane flies over your head

    Suppose a supersonic airplane has Mach number MM. It flies horizontally. At some time, it flies past over your head at height hh. Then, the distance between you and it when you have just heard it is MhMh.

  • Nov 16, 2022

    Finding curvature radius physically

    Sometimes the curvature radius of a curve can be found by using physical methods although it seems that you must use calculus to find it. In this article, the curvature radius of the curve x2=2pyx^2=2py at the point where the curvature radius is smallest is found by using physical methods without using calculus (with only high school knowledge). The answer is that the smallest curvature is exactly pp, and the point with smallest curvature is the vertex.

  • Nov 16, 2022

    A whirling point charge

    In the vacuum, inside a fixed ring of radius RR with fixed charge QQ uniformly distributed, there is a point charge with charge qq and mass mm moving in the plane of the ring due tue the electrostatic force. It moves in the small region around the center of the ring, and the motion is periodic along a closed curve. The area of the region enclosed by the curve is SS. Denote the distance from the center to the point charge as rr, and r≪Rr\ll R. Find the magnetic induction BB at the center of the ring.

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